SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf2e12fba3c5c8afb0f00869a8c20e5f881641b4dba62861af8b6497f239396f' 
  AND token = '7dTt6Oh+f8MftUZt8zTIra8/xICT283ptiUVld5BdIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}